Teenager Fabiano Joseph claimed the IAAF World Half Marathon crown in Edmonton after a dramatic finish.
Joseph finished a second ahead of Shami
The 19-year-old Tanzanian pipped Mubarek Shami of Qatar with his final stride to make up for finishing second in the race for the past two years.
Shami, formerly of Kenya, raised his arms in celebration, thinking victory was his, only for Joseph to pass him.
Joseph won in a time of 1hr 1min 8secs. Eritrea's Yonas Kifle claimed third place in 1:01.14.
Cold temperatures and steady rain meant that the times were well off world record pace.
Afterwards, Shami admitted: "I was thinking I had won the race. But I'm not disappointed. Competition is like that, and I'm very happy with my silver medal."
Joseph said: "Shami celebrated too early, and I was very happy to finish first."
The team title went to Ethiopia, led by Sileshi Sihine on his half marathon debut.
The world 5,000m and 10,000m silver medallist led Ethiopia to their first team success since Haile Gebrselassie inspired them to victory in 2001.
Mara Yamauchi led the British women's team to fifth place in Edmonton.
Yamauchi, who finished 18th behind Romanian individual winner Constantina
Tomescu-Dita, was first home for Britain in one hour 12 minutes and 40 seconds.
Scotland's Hayley Haining and Susan Partridge, who ran together in the latter stages, finished 24th and 25th respectively in 1:13.39 and 1:13.49.
Debbie Mason, back in action after a hamstring injury, took 52nd position in